Viper Scale Racing | 7T vs. 8T vs. 9T Drag Strip Results
About the Test
This test compared 7-tooth (7T), 8-tooth (8T), and 9-tooth (9T) pinion gears on a Viper V1 to see how pinion size affects
acceleration and top speed. The pinions tested were prototype metal goose neck pinions, run with a Viper 23T black crown
gear. Testing was conducted by Viper Scale Racing on an HO scale 1,000′ drag strip with the track power set to 18 volts.
Each pinion was run repeatedly down the strip (R1, R2, R3, and so on) under the same conditions, and the elapsed time (ET)
in seconds and speed in MPH were recorded for every run. The 7T and 8T pinions each completed 7 runs and the 9T
completed 5 runs. Averages, slowest, and quickest/fastest results are shown for each pinion.
Conclusion
The 8T pinion was the quickest and the best overall match for this motor, magnet, and tire combination. The 9T results were
not a surprise: at a 2.56:1 gear ratio, it is a lot of gear for this motor, these magnets, and these tires to pull. The 9T is typically
better suited to higher-powered motors in drag-racing-only applications. For a road course setup, the 7T remains my primary
choice.
